import Vue from 'vue'
import VueRouter from 'vue-router'
import Login from '../components/login.vue'
import Home from '../components/home.vue'
import Welcome from '../components/welcome.vue'
import Users from '../components/user/users.vue'

Vue.use(VueRouter)

  const routes = [
    {path: '/',redirect: '/login'},
    {path: '/login', component: Login},
    {path: '/home', component: Home, 
    redirect: '/welcome',
    children: [
      {path: '/welcome', component: Welcome},
      {path: '/users', component: Users},
    ]}
]

const router = new VueRouter({
  routes
})




// 挂载路由导航守卫
router.beforeEach((to,from,next)=>{
  // to 将要访问的路径
  // from 代表从哪个路径跳转而来
  // next 是一个函数，表示放行
  //  next() 放行  next（"/login"） 强制跳转
  if(to.path==="/login") return next()
  // 获取token
  const tokenstr=window.sessionStorage.getItem('session')
  if (!tokenstr) return next('/login')
  next()
})

// 解决ElementUI导航栏中的vue-router在3.0版本以上重复点菜单报错问题
const originalPush = VueRouter.prototype.push
VueRouter.prototype.push = function push(location) {
  return originalPush.call(this, location).catch(err => err)
}

export default router
